Effect of Textile Cylinder on the Production of Distillate in Solar Desalination

Abstract

Bangladesh has become one of the most populated and climate vulnerable countries ill the world. The water scarcity coupled with a significant growth in population and climate vulnerability especially in coastal areas of Bangladesh and POSCS the serious problem of supplying fresh water. But in the world of these areas, water is available in abundance but most of' them are saline that is why there is a shortage of potable water. Considering this issue, numerous technologies have been developed around the world to distillate water in which some of those are used in Bangladesh. The standard techniques, like multi-stage flash (MSF), multi-effect (ME) vapor compression (VC), and reverse osmosis (RO), are only reliable for large capacity ranges from 100 50,000 m3/day, expensive for small amounts of fresh water production and cannot be used in locations where there are limited energy - supplies. Due to the fossil-fuel-based energy consumption, emissions of greenhouse gases - (e.g. CO2. CO and SO2) will always be an issue of environmental concern. Even though, in the coastal and remote areas of Bangladesh like St.Martin, Nijhoom Island which are located far away from the energy grid-lines require a local source of energy to desalinate water from its available sources. In the context of the crisis, solar desalination seems to be the most suitable solution option of salinity problem for the coastal areas of Bangladesh. Solar desalination technique would also have promising application because of its environment friendly nature. Thus, solar desalination has become one of the important non-conventional water resources that play a significant role in solving fresh water scarcity of the global community, especially the coastal areas of Bangladesh. But the main disadvantage of a simple solar desalination is its low production efficiency. The production efficiency depends on the temperature difference between the water surface and the glass covers, water surface area and other atmospheric parameters.

In this study, the evaporation surface area of the solar still has been taken into account and sought a way that how it can be increased. In the mean time, got an innovative idea to increase the evaporation surface area and that is outer surface area of a cylinder which seems to he a suitable option. To evaporate water from the outer surface of the cylinder, water must he retained or absorbed along its surface. That's why the textile has been selected and formed into cylindrical shape with the help of an aluminum wire cylindrical frame. The spiral frames have been made by using aluminum wires. The inner cylinder were covered by different types of textile and inserted into a transparent plastic outer cylinder. The whole system has been installed on the roof top of the 3-storey building of Environmental Engineering laboratory For monitoring its production efficiency. The distillate production rate (DPR) and distillate quality parameters, salinity, electric conductivity and pH have been monitored and the durability of the textiles has also been investigated in different salinity. The maximum DPR was Found 11.11 L/m2/day and water quality parameters were below the drinking water standard limit. The durability of the setup was observed 3-4 years and its durability would he increased by proper operation and maintenance. This textile cylinder can he used in the coastal areas of Bangladesh where the people are suffering from salinity problems. It can also be suitable For a few families or small groups in remote areas.